Hi @Venkataramudu A 
Ensure there are no extra spaces in the email addresses. also the "Contributor" field is of type string or array that can handle multiple values correctly.
Use join(',') for proper formatting of multiple sys_ids.

answer = (function transformEntry(source) {
    var contributors = [];
    var con_email = source.u_contributors.split(',').map(function(email) { return email.trim(); });
    
    if (source.u_contributors) {
        for (var j = 0; j < con_email.length; j++) {
            var gr_user1 = new GlideRecord('sys_user');
            gr_user1.addQuery('email', con_email[j]);
            gr_user1.query();

            if (gr_user1.next()) {
                contributors.push(gr_user1.sys_id);
            } else {
                gs.warn("Contributor " + con_email[j] + " doesn't exist in ServiceNow for policy " + source.u_name);
            }
        }

        var contributors1 = contributors.join(',');
        return contributors1;
    } else {
        gs.warn("Contributors are not defined for " + source.u_name + " policy");
    }
})(source);

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